Working with ORDA optimistic locking
4D v17 introduces ORDA, a major evolution in 4D which is opening a world of new possibilities for 4D developers. One of the benefits of using ORDA is related to record locking, because ORDA offers a choice between optimistic and pessimistic locking. After having introduced the ORDA locking mechanisms, we continue the ORDA series so you can discover how to work efficiently with optimistic locking with ORDA.
Locking entities with ORDA
The ORDA series continues! In this blog post, we’ll look at how you can use locks in your databases with ORDA concepts! It’s not uncommon to need to manage conflicts that might occur when several users or processes load and/or attempt to modify the same records at the same time. Record locking is a methodology used in relational databases to avoid inconsistent updates to data.
ORDA provides an optimistic locking mode in addition to the one you already know (pessimistic locking).
Loops, loops and … more loops!
Like many other programming languages, 4D provides the ability to iterate over numbers with a For(…) / End for statement, or over a condition thanks to the While(…)/End while and Repeat/Until(…) keywords. These iterations (or loops) are very useful, but not the most appropriate way to iterate over advanced data types such as collections and entity selections. That’s why the new For each(…)/End for each iterator has been created, to help ease your coding!
How to create a dynamic form from a table in 3 steps!
4D v17 includes dynamic forms, initially introduced in 4D v16 R6, a powerful and flexible way to dynamically build forms fully adapted to your end users’ needs. The possibilities of dynamic forms are tremendous. In this post, we’ll see a concrete example of what you can do with these new forms.
ORDA: work with objects and collections
In this latest addition to the ORDA series, we’ll look at how the new ORDA concepts can interact with existing objects and collections. In fact, it’s possible to turn entities and entity selections into objects and collections, as well as build entities and entity selections from objects and collections. By doing so, you can easily integrate ORDA code within your existing code. You can take full advantage of ORDA without needing to rewrite your code!
Going back and forth between current selections to ORDA
ORDA is a major innovation of 4D v17, this is why we’re dedicating an entire series of blog posts to ORDA. While ORDA has its own concepts that are very different from the classic approach, it’s still possible to mix ORDA with your existing code.
In a nutshell, this blog post will show you how you can update the current selection of a table from an entity selection and get an entity selection from the current selection of a table. It’ll allow you to smoothly integrate ORDA concepts into your existing 4D code, step by step.
Display a collection in a listbox
Recently, 4D introduced of a new type of variable: collections, as well as a large set of methods to manipulate them. With 4D v17, the possibilities of collections is becoming larger by being able to easily display the content of a collection. How? List boxes of collection type!
Query your database with an object-oriented approach
After learning how you can create, update, and delete data, here is a new entry in the ORDA series. In this post, you will see how you can query your datastore in an object-oriented mode. With ORDA, queries are lighter, more readable, and you can navigate through the whole data model using object-oriented concepts !
On top of that, ORDA makes it possible to very easily query several related tables, manage recursive relations on the same table, and use several logical operators in a single query. Plus, you don’t have to worry about setting relations between tables … manually or automatically !
Create, update and delete data with ORDA
4D v17 introduces ORDA, a major evolution in 4D which is opening a world of new possibilities for 4D developers. To learn more about ORDA and its benefits, check out this post to see how ORDA will change the way you work. In order to guide you through the ORDA exploration, we’ve prepared a series of blog posts fully dedicated to the core concepts and related features. This blog post will detail how you can perform CRUD operations on your database with ORDA. CRUD is an acronym for the four basic operations you can perform on data: Create, Read, Update, and Delete.
How ORDA will change the way you work
Imagine a way of using your database with an object-oriented approach, without worrying about its physical structure. Imagine that you could maintain multiple current selections at the same time or that you could perform recursive queries in a single line of code. Well, this is now a reality thanks to ORDA! With 4D v17, your code can be written in an object-oriented mode, and you can easily navigate through your entire data model.
ORDA was one of the major announcements of 4D Summit 2018, opening a world of new possibilities in 4D. It’s now time to give you more details about the ORDA features available with 4D v17. To do so, we’ve prepared a series of blog posts dedicated specifically to ORDA core concepts and related features. And we’ll release them, one after another, day after day.
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